Watch: Keeping out birds lets in pests

The netting used on live oak trees in Texas may do a good job of keeping out bothersome birds such as grackles and pigeons, but research shows their absence may allow venomous caterpillars, known as asps, to increase. Looking at the oak trees on the sidewalks of the Texas Medical Center, the researchers found that keeping out the birds that often eat the insects has caused the asp (Megalopyge opercularis) population to thrive. The researchers discovered the caterpillars were more than 7,300% more abundant on netted trees than non-netted trees. The venomous insects can sting people, causing severe pain and even symptoms like headaches, nausea, vomiting, fever, and more. The researchers said the study shows changing natural interactions, even in urban settings, can have unintended consequences.

Check out the study in Biological Lettershere, and watch a video about the research below.